distinguish between reliability and validity in research design

However, they have different purposes and focus on different aspects. Validity and reliability are closely related concepts. Differences between validity and reliability The same happens in research and with all the instruments from which we obtain measurements, such as psychometric tests. If we observe that we obtain very different values in each one, we can affirm that it’s not reliable. That’s why we carry out several measurements. If we only weigh the object once, we can’t affirm that the measurement is reliable. Let’s go back to the example of the scale.

What’s usually done is to compare the measurement we obtain, with that given to us by an instrument that we know is reliable. For example, say we’re measuring the anxiety experienced by a subject. It’s the degree to which an assessment tool produces consistent results by measuring the same thing under the same conditions.Ī common procedure for obtaining the reliability of an instrument is to have it measure the same unchanging variable several times. Reliability is understood as the consistency or stability of the measurements when a measurement process is repeated (Prieto and Delgado, 2010). It means we’re able to trust the data obtained from that particular research design, the acquisition of data, the analysis of data processing, the interpretation, and its resulting judgment (Cohen, Manion, and Morrison, 2018). In general, it is considered that the results of an investigation will be valid when the study is free of errors”(Villasís-Keever, 2018).ĭetermining validity is essential for all research.

On the other hand, in an investigation, the concept of validity “refers to what is true or what is close to the truth. Therefore, if an anxiety test that claims to measure you doesn’t perform, then it’s invalid. If we couldn’t make such a measurement, then the scale wouldn’t be valid for that specific task. However, when we refer to it in the field of psychometry, we refer to the degree to which the instrument measures the variable to be measured (Hernández-Sampieri, Fernández & Baptista, 2014).įor example, if a scale allows us to know the weight of an object, we can affirm that it’s valid to the extent that it fulfills the function for which it was designed. In order to understand a little about the distinction between validity and reliability, you need to know what they are.

However, how do, validity and reliability differ? In fact, using more or less valid or reliable instruments can add or subtract value to a study itself. Validity and reliability are two key constructs in the analysis of the results produced by psychological studies.

Distinguish between reliability and validity in research design